National Security Agency
(NSA) The National Security Agency/Central Security Service is America’s cryptologic organization. It coordinates, directs, and performs highly specialized activities to protect U.S. information systems and produce foreign intelligence information. A high technology organization, NSA is on the frontiers of communications and data processing. It is also one of the most important centers of foreign language analysis and research within the government.

Source:
http://www.nsa.gov/about/index.cfm